Why does g-force make you faint?
Lily Fisher
Updated on May 25, 2026
Your brain cells hold a small oxygen reserve that can keep them functioning for about 4 seconds, Fan said. After that reserve is depleted, the brain will "shut down," causing you to lose consciousness as the boy in the GIF did. This is
G-LOC
g-force induced loss of consciousness (abbreviated as G-LOC, pronounced "JEE-lock") is a term generally used in aerospace physiology to describe a loss of consciousness occurring from excessive and sustained g-forces draining blood away from the brain causing cerebral hypoxia.
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